On Fri, 2007-12-21 at 10:00 -0800, [EMAIL PROTECTED] wrote: > On Fri, Dec 21, 2007 at 07:56:25AM +1100, Benjamin Herrenschmidt wrote: > > ... > > Can't you just have a primitive to sync things up that you call > > explicitely from your driver after fetching a new status entry ? > > > > Well, the only mechanisms I know to get things synced are the ones > I mentioned before: 1) generate an interrupt, 2) write to memory > which has the "barrier" attribute. Obviously 1 is out - giving > the memory used for status indications the barrier attribute is > the most primitive means I'm aware of.
Well, I'm not totally against turning "direction" into a flag mask, as I do have requests to do something similar on some PowerPC's in fact in order to control the ordering guarantees of a given DMA mapping (ie. relaxed vs. fully ordered). I'm just worried that we'll end up with as many semantics for those flags as we have host bridges & archs around, which would be bad. Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
